1. Field of the Invention
The present invention relates to a configuration of a frame for a speaker device.
2. Description of Related Art
Conventionally, there is known a speaker device including a vibrating system having a frame and a diaphragm, and a magnetic circuit system having a yoke, a magnet and a plate.
In such a speaker device, the frame is formed into a bowl shape, for example. The frame having such a shape includes a frame central portion holding a magnetic circuit, an outer peripheral portion disposed on an outer side of the frame central portion and having an edge mounting portion on which an outer peripheral portion of an edge is mounted, and plural arm portions connecting the frame central portion and the outer peripheral portion.
Particularly, on the frame having such a configuration, the plural arm portions are provided to radially extend from a center of the frame to the outer peripheral portion. Examples of the frame having the configuration of this kind are disclosed in Japanese Patent Applications Laid-open under No. 7-38992, No. 2004-312338, No. 8-70495 and No. 5-347795.
In the speaker device according to the above-mentioned documents, the arm connecting the frame central portion and the outer peripheral portion is mainly designed for the purpose of securing mechanical strength. The arm in which ribs for securing the strength are formed on both edges of a plate is frequently used, and a sectional shape thereof is formed into an “H” or “η” shape. However, since the arm having the “H” or “η” shaped sectional shape includes a plane surface, a resistance to an air flow is large on an flat portion thereof. Therefore, it is problematic that the resistance to the air flow in both directions between the frame central portion and the outer peripheral portion easily becomes unequal at the time of the driving of the speaker.